Puppet-valve for internal-combustion engines



F. D. SHEPHERD.

PUPFET VALVE FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED Auen, 1919.

Patented Feb. 24, 1920.

2 SHEETS-SHEET I.

F. D. SHEPHERD.

P'UPPET VALVE FOR INTERNL COMBUSHON ENGINES.l

APPLICATION FILED M1627. new.

1,33 1,826. A Patented Feb. 24, 1920.

2 SHEETS-SHEET 2 i guidel is mounted and FRANK D. SHEPHERD, oF Limena, ILLINOIS,-

rUrPE'r-vALvE Eon IN'rEENAncoMEUs'rIoN ENGINES.

Specication of Letters Patent. v

Patented Feb. 24, 1920.

Application led August 27, 1919. Serial No. 329,273.

To all whom t 'mag/concern.'

Be it known that I, FRANK D. SHEPHERD,

'of Aurora, Illinois, have invented a certain new and useful Improvement in Puppet- '.'Valves for Internal-'Combustion y Engines, and do`- hereby declarethat theifollowlng'is a full, clear and vexact description thereof.

My invention relates to puppet valves for internal combustionengines. I have discovered that localized wear of the valve stem, with consequent cooking of'the valve and its failure to seat properly, is due to lateral deformation or buckling of the fairly long coil spring commonly used to move the valve to 'its Seat, which results in side pressure, and my object, generally stated, and primarily, is `to prevent thennbalanced side pressure on the stem and thus avoid the localized wear which is objectionable, not only in itself, but in its results in impairing ,the efliciency ofthe engine and wasting fuel, and preventing that .jquick seating of the valve bv the spring which is so important. I have also had in view such construction of parts as will most eiiciently attain such object and will be best suited for the purpose 'from the standpoint ofthe manufacturer and the'repairer.

My invention consists inthe construction as a whole and in the parts thereof-substantially as hereinafter specified and claimed.

In the accompanying drawings:

Figure 1 isa vertica section' of a gas enine to illustrate one embodiment of my invention;

Fig. 2 is a vertical section showing a form of my invention in which the contamer and placed differently` from what is shown in Fig. 1;

Fig. 3 is a detail end view;

Figs. 4 and 5, are, each a similar View of another embodiment of my invention;

Fig. 6 is a detail view in cross section on line 6--6-of Fig. 5;

Fig. 7 is a side view of the spring guide or container ofyFig. 5.

. My invention 1s not limited in its application to any particular construction of engine so that the latter may be of an L-head or T-head type, with an integral or detachable head. I 'illustrate my invention in the c ameter that when the, spring 1s thus comdrawings as applied to an engine of-an L- head type, and to engines with detachable and integral heads. The valve mechanism may be the same for both intake and exhaust, but in Fig. 1, I show an enginev in which it is applied only to the exhaust. As my invention is not concerned with the valve `lifting mechanism, I illustrate' the Well fknown cam device for that purpose.

In thev drawings lO'designates the cylin'-- der, 11 the piston; therein, 12 the head which may be detachable as shown in Figs. 1` and 2, or integral as shown in Fig. 4, 13 the valve seat, 14 the valve head for controllingl communication between the cylinder 10 an the chamber 15, (either the intake or the exi haust)4 and l 16 the valve stem-having .its free end reaching to a point whereit' can be engaged by the rod or plunger 17 actuated by the cam.

The chamber 15 is open throughout its length from-the Vvalve seat 13 to its opposite 'end and withinthe same and beyond the port '18 which leads into or from the chamber 15 is a tubular or cylindrical hollow -body 19. The valve vstem 16 passes centrally through the bod 19, and has a'sliding fit within a guide t erem` At the lower `end thereof, 'or the end farthest from the valve 14, the stem has a 'disk or collar 20,

upon it to form a thrust bearing for one end of a coil springl 21', that surroundsthe valve stem and the valve stem guide within the body 19 that extends down fromthe head 22, and Whose other end has a thrust bearing against head 22. The spring acts to hold the valve head 14 against its seat and'when lifted by thecam, it returns to' its seat when the campermits it. v

To check and prevent any buckling or sidewise deformation of the spring, I give its coils such external diameter relative to the internal diameter of the body 19 that at the4 time of greatest, compression of the spring, which is the time the valve is off its seat, such coils will engage lthe interior buckling and compelled to act-.upon the `valve stem in a dlrection wholly parallel pressed, its coils will engage with the vinclosing body/ 19 and'it is when the valve 4of the body and thereby be restrained from' fit against the resistance to free movement of the disk,-

and of the valve stem, with which the disk is connected as hereinafter explained, so that pressure of the spring is transmitted to the stem, or movement of the stein, when lifted by the cam, is transmitted to the disk.

The disk has a central hole 23 through which the valve stem passes, said hole being sufficiently larger than the valve stem as to leave ya clearance between the sides of the hole and stem, and thus allow side play of the parts without contact of stem and disk. This makes unnecessary the accurate, and,vhence, costly fitting of the parts which would be necessary did the disk have a snug or close fit upon the stem. With a snu or close fit of disk and stem, should theree any want of alinement or concentricity of the stem-guiding hole in the body 19 and the disk-engaging interior of the body 19, obviously close fit of stem and disk hole would result in binding of the parts after assembled and in operation and, hence,

v accuracy of fitting of the parts even to the thousandths of an inch would be necessary. The disk 20 has a main or web portion lwhich contains the hole 23 through which the stem passes, and as shown in Figs. 1 and 2, an upwardly extending flange or rim 24 and as shown in Figs. 2, 4 and 5 a downwardly extending flange or rim 2.5 to give van elongated lbearing on its 4periphery against the interior of the body 19.

The hole 23 is made so large that a substantial space exists between the wall thereof l and the stem, so that even should wear and side play of the disk occur, it would not reach and exert pressure on the stem. As a gas-tight fit of the stem in the stem guide 1s provided, the presence of the large hole 2'3 in the disk, leavin a space aroundthe stem, is not objectiona le for no air passing through the hole can enter and injure the charge fiowing to the cylinder past the open intake valve. That is to say, between the valve and the intake port and the disk the stem passes through a gas-tight guide hole. The connection between the disk 20 and valve stem\ by which they move together is in the form of a cross pin or key driven through a hole in the stem, or engaging a groove-in the stem and'projecting on oppo- 1 site sides of thestem and engaging the underside -of the disk web, vas in Fig. 4, or a washer, so that the pressure of the spring ody 19 and an keeps the disk or washer in contact with site sides thereof and seated at its pro]ect ing ends in a diametrically extending groove or recess 28 in the underside of washer 26.

The pin may `be rectangular in cross section as shown in Fig. 2, or it may be round as shown in Fig. 1.` While the washerv has a close fit upon the valve stem'there is a clearance between its periphery andthe downwardly extending flange 25 of the disk 20 which permits such relative sidewise movement of the disk 2O and stem as may be necessary to compensate for any irregularity of alinement of the parts.

As shown in Figs. 4, 5 and 6, the key is in the form of a AU-clip 29 that straddles the stein, and is seated in an annular groove 30, therein.

To facilitate the insertion and removal of the pin or key, the guide or container 19, at its bottom, has diametrically opposite notches 190, of a size to permit the passage of the pin or key, the ldisk 20 and washer 26.

of course being Ipressed up in -the guide to expose these notches. The initial pressure of the spring on the valve 'results from this key-inserting operation.

referably as shown in each of Figs. 1, 2, 4 and 5, the periphery of the disk is provided with. one or more small gannular grooves 31 to receive a lubricant.

It will be seen that in each form of my invention that as far as turningfmovement is concerned there is a loose connection between the disk and the stem so that the valve -head Mis free to turn with reference to its seat, and will not always contact with its seat inthe same position, and thus localized wear lon valve and seat and leakage is prevented. y

Preferably the wall of the body 19 is provided with openings or perforationswhich may be mere holes 32 as illustrated in Figs.

2, 4 and 5, or elongated openings or slots 33y as illustrated/ in Figel, these openings or perforations serving the purpose of allowing the free passage of air-so as lto avoid any interfere-nce with the free action of the valve,

and for supplying oil to the interior of the body 19. The slot form of opening'is an advantage inthat it makes va lighter foonstruction.

In the embodiment of my invention illusf trated in Fig. 4, the rbody or member 19 is secured in place byh'aving at its upper or in-v nerl end an annular flange or shoulder 34 which engagesa seat 35 on the wall of the chamber 15, and a lockring or nut 36 whichl engagesthread on the exterior of the body 19 and abuts a ainst the surfaces around the open outer en of the chamber 15. In some cases, however, as in small engines with a light exhaust, the shoulders 34 and 35 may be 'omitted and in place of the lock ring 36 an integral flange 37 (see Fig. 5) may be provided to engage the surface adjacent the open end ofthe chamber 15, the portion of the body or member 19 wit-hin the chamber 15 having a tight fit therein. In this lastnamed case, the pressure of the spring 21 against the head 22,01? thebod 19, is in the direction to 4keep the body in p ace.

In Fig. 2, the body 19 instead of having" a friction fit within the chamber 15 has a screw4 thread connection therewith.v

As shown in Fig. 1, the members of the body or member 19 ma be made in one plece and a friction connection made between thel is in the same direction, and the inner spring 1s restrained from buckling and interlocking y its coils-:with the outer spring by an internal tubular extension 39 of the body or member 19. In Fig. 5the pitch of the coils is opposite, and as thereby interlocking of coils is prevented, I use the outer spring as the means to prevent buckling of the inner spring by making their diameters such that on compression when the valveis lifted, the coils will have peripheral contact. By multiplying and -nesting the4 sprin the coils can be of lighter age than wen a single spring is used, an in consequence the two springs are more flexible, and quicker to act, and that means closer following of the cam and quicker seating of the valves, and con-y seouently increase of efiiciency of the engine.

It is to be understood that thev elements going to make up the construction shown in any one'gure of the drawings may be differently combined. For example, for the single spring shown in Fig. 1, maybe substituted the double spring shown 'in Fig. 4, and for 'the spring-engaging disk construction lshown in Fig.'-5 may be: substituted the l spring-engaging disk' construction shown in what 'intim isf- 1 Fig 1 1'. In an internal combustion engine, the

combination of a valve, havingv a stem, a

valve stem guide, an expansively acting coil spring srroundingthe stem having a fixed 'bearing'at one end, a bearing for the other end of the spring to transmit pressure 'from the spring to the stem through which the stem passes, a clearance space existing between the stem and the bearing that permits relative lateral movement 'of the bearing without contact with .the stem, a loose connection between the Zbearing and the stem that' permits such lateral movement, said bearing having guiding contact withv said guide, the coils of the spring engaging with the guide sides when the spring is compressed, and the valve is off its seat, whereby the spring is restrained from lateral deflection.

2. In an internal combustion engine, the combination of avalve having a stem, controlling communication between the cylinder and a chamber,'a valve sternextending from the chamber through. a hole Ain which it has a sliding gas tight fit, a spring surrounding the stem and acting at one end against a stationary part, a bearing for the other end of the spring to transmit pressure from the spring tothe stem through which the stem passes, a clearance space existing between the stem and the bearing that permits relative lateral movement of the bearing without contact with the stem, a loosev connection between the bearing and the stem thatpermits such lateral movement, and a container with whichv said rbea-ring has sliding contact and with which the coils of the spring engage when the spring is compressed and the valve is off its seat, whereby lateral deflection of the spring is restrained.

A3. In an internal combustion engine, the combination of a valve havinga stem, controlling communication between the cylinder and a chamber, a valve stem guide extending-from the chamber having a hole in which the stem has a sliding gas tight fit, a

spring surrounding the stem and acting at one end against said guide, a bearing disk for the other end of the spring loosely mounted upon the stem to transmit pressure from the spring to the stem through which the stem passes, a clearance space existing between the stem and the bearing that perymits relative lateral movement of the bearing without contactwith the stem, a loose connection between the bea-ring and the stem that permits such lateral .movement, and means supporting said disk against sidewise thrust and with which the coils of the spring engage when the spring is compressed and the valve is off its seat,v whereby lateral deflection of the'spring is restrained.

4. In 'aninternal combustion-engine, the combination of a valve having a valve stem, a valve stem guide, ran expansively acting coil spring surrounding the stem having a fixed bearing at one end, a bearing for the other end of the spring` loosely mounted upon the stem to transmit pressure from the spring to the stem, saidibearing havingl guidingcontact with said guide, the coils of the spring engaging `with. the guide sides when the' sprmg isI compressed, and the valve is olf its seat,` whereby the spring is 4restrained from lateral deflection, and a second coil spring Within the other and interposed between the same bearings.

In an internal combustion engine, the combination of a valve having a valve stem, a valve stem guide, an eXpansively acting coil s ring surrounding the stem having a fixed earmg at one end, a'bearing for the other end of the spring loosely mounted upon the stem to transmit pressure from the -snin to the stemy said bearinf havin a g a a:

guiding contact with said guide, the coils of the spring engaging with the guide sides when fthe spring is compressed, and the valve 4 is off its seat, whereby the spring is restrained from lateral deflection, and a second coil spring within the other and interposed between the same bearings, the two springs having their coils of opposite pitch.

6. 'The combination in an internal combustion engine of a/puppet va1ve,'a stem, a member with a. hole through which the stem slides, a coil spring Within the member, act

, ing to seat the valve, and encircling the stem,

a spring-engaging disk in said member having a hole through which the stem passes, and a cross key engaging the stem and situated on the side of the .disk opposite the spring, said member having its Wall notched to register with the key to provide space for i the endwise movement of the key in assemare. assembled for'the p 7. The combination 1n an internal combling the parts, and means to prevent end- Wise movement. of the key when the parts passage of said key.

bustion engine of a valve-controlled passage in communication with the cylinder, a valve situated in such passage, a ste-m reaching from the Valve through the assage and to the exterior thereof throng guide, a coiled spring through which the stem passes, a relatively stationary bearing for one end of the spring, a bearing for the other end of the spring movable with the stem in both directions, said bearing having a gas tight a hole through which the stem passes substant-ially larger in diameter than the stem to permit lateral movement without contact of stem and bearing, and a guide engaging the outside of the bearing.

8. In an internal combustion engine, the

combination of a valve having a stem, con-v trollin communication between the cylinder and a c amber, a valve stem guide extending from the chamber having a hole in which the stem has a gas tight fit, a spring surroundingsaid guide and the stem acting at one endagainst said guide, a bearing disk for the other cnd of the spring loosely mounted upon the stem to transmit pressure from the spring to the stem and means supporting said diskagainst sidewise thrust.

In testimony that I, claim the foregoing I have hereunto set m hand.

' FRA K D. SHEPHERD. 

